The invention relates to composite self-lubricating bearings, and more particularly to link chains and universal couplings.
In the past, link chains comprising links including respective apertures, together with bushings respectively fixed in the apertures, and hinge pins respectively extending through the bushings were known. In these past constructions, the bushings included composite bearings with annular, inwardly facing self-lubricating bearing surfaces in engagement with the hinge pins. In these past constructions, the tension loads transmitted during linear and arcuate movement and between the bushings and the hinge pins occurred along a line extending axially of the composite bearings and the resulting wear on the composite bearings was concentrated along this line.
Also in the past, universal joints comprising generally identical first and second members respectively including pairs of spaced arms with aligned apertures, together with composite bushings respectively fixed in the apertures of the spaced arms and respectively including inwardly facing self-lubricating bearing surfaces, were known. These past constructions also included a yoke member including a central portion, together with a first pair of axially spaced and aligned stub shafts which extended radially outwardly from the central portion and into engagement with the inwardly facing self-lubricating surfaces of the bushings fixed in the first member, and a second pair of axially spaced and aligned stub shafts extending radially outwardly from the central portion in 90 degree angular relation to the first pair of stub shafts and into engagement with the inwardly facing self-lubricating surfaces of the bushings fixed in the second member. As in the case of the link chains referred to above, the loads transmitted during arcuate relative movement between the yoke member and first and second members principally occurred along a line extending axially of the composite bearings and the resulting wear on the composite bearings was concentrated along this line.
Attention is directed to prior U.S. Pat. No. 5,265,965, issued Nov. 30, 1993, which is incorporated herein by reference. Attention is also directed to U.S. Pat. No. 3,700,295, issued Oct. 24, 1972, and U.S. Pat. No. 3,974,009, issued Aug. 10, 1976. Attention is further directed to U.S. Pat. No. 5,288,354 issued Feb. 22, 1994, and incorporated herein by reference.